Since the blue LED chip has come forth, the LED lamp has been developing rapidly. The blue LED chip is used as an excitation light source to excite the YAG phosphor to produce yellow light, then the yellow light is mixed with the rest of the blue light of the blue chip except the portion which excites the phosphor to produce white light. This white LED has high efficacy and high color rendering in high color temperature, however, the color rendering in low color temperature is too low to meet the requirement of general illumination. Therefore, for resolving the problem of the above-mentioned problem, generally, the red LED phosphor is added into the yellow phosphor to enhance the red light of the white LED so as to increase the color rendering index, but this will reduce the luminous flux too much, thus it is not applicable. The method of adding red LED lamps to the white LED lamp was disclosed in the patent of U.S. Pat. No. 6,577,073B2, 2003, which can reduce the color temperature of the white LED lamp to increase the color rendering index. However, normal blue LED chips only have lower power, and each granule only has two chips (one blue LED chip and one red LED chip). The white LED is formed by adjusting the intensity of the blue LED chip and red LED chip respectively. Accordingly, this needs a complex control circuit and is hard to adjust, thus it needs to be improved further.